#include <bits/stdc++.h>
using namespace std;

int n, k;
int a[1010];
/**
 * 
 * 时间复杂度 O(n^2)
 * 空间复杂度 O(1)
 * 
 * 找和为k的两个数
 * 
 */
int main() {
    cin >> n >> k;
    for (int i = 0; i < n; ++i) {
        cin >> a[i];
    }
    for (int i = 0; i < n; ++i) {
        for (int j = i + 1; j < n; ++j) {
            if (a[i] + a[j] == k) {
                cout << "yes" << endl;
                return 0;
            }
        }
    }
    cout << "no" << endl;
    return 0;
}